Heretofore known in the art is a technique of estimating whether or not a moving object crossing a pedestrian crosswalk and a subject vehicle come close to each other (WO2011/086661).
The prior art is, however, to detect only a moving object crossing a pedestrian crosswalk located ahead. Thus, an object before crossing the pedestrian crosswalk, that is, an object that may move to come close to the subject vehicle when the subject vehicle approaches the pedestrian crosswalk, cannot be detected before the subject vehicle comes close to the pedestrian crosswalk. This may be problematic.